Multiple spring socket for pin connector

ABSTRACT

The connector of the invention includes a positive spring loaded contact which grips and retains the connector pin under severe temperature and vibration conditions. The contact assembly consists of a cylindrical socket having a spring retaining slot to receive a plurality of resilient, leaf springs curved along the longitudinal axis. The springs are of a different width to provide a tapered, multi leaf, spring assembly which projects into the bore of the socket and is fixedly retained by a retaining sleeve which slides over the socket. By virtue of the plurality of thin, resilient, leaf springs, the proper contact spring pressure on the pin may be maintained even under conditions of high vibration, while at the same time, avoiding permanent deformation or set of the spring by the pin. That is, by using a plurality, preferably three, individual springs, each spring can be very thin and flexible and can undergo substantial deflection without producing permanent deformation of the individual leaf spring. Simultaneously, by using a plurality of springs, the spring pressure necessary to retain the pin firmly in the socket even under high vibration conditions is provided. Damage by permanent deformation of the springs due to oversize socket pins or due to the improper use of test probes is prevented since the retaining sleeve limits permanent deformation.

United States Patent [191 Pustell et al.

[ Dec. 23, 1975 MULTIPLE SPRING SOCKET FOR PIN CONNECTOR [75] Inventors: Robert Algerd Pustell, Melrose; Thomas Parker Haselton, Lynn, both of Mass.

[73] Assignee: General Electric Company,

Wilmington, Mass.

[22 Filed: June 5,1974

211 Appl. No.: 476,524

Primary ExaminerJoseph H. McGlynn [57] ABSTRACT The connector of the invention includes a positive spring loaded contact which grips and retains the connector pin under severe temperature and vibration conditions. The contact assembly consists of a cylindrical socket having a spring retaining slot to receive a plurality of resilient, leaf springs curved along the longitudinal axis. The springs are of a different width to provide a tapered, multi leaf, spring assembly which projects into the bore of the socket and is fixedly retained by a retaining sleeve which slides over the socket. By virtue of the plurality of thin, resilient, leaf springs, the proper contact spring pressure on the pin may be maintained even under conditions of high vibration, while at the same time, avoiding permanent deformation or set of the'spring by the pin. That is, by using a plurality, preferably three, individual springs, each spring can be very thin and flexible and can undergo substantial deflection without producing pennanent deformation of the individual leaf spring. Simultaneously, by using a plurality of springs, the spring pressure necessary to retain the pin firmly in the socket even under high vibration conditions is provided. Damage by permanent deformation of the springs due to oversize socket pins or due to the improper use of test probes is prevented since the retaining sleeve limits permanent deformation.

2 Claims, 3 Drawing Figures U.S. Patent Dec. 23, 1975 MULTIPLE SPRING SOCKET FOR PIN CONNECTOR The socket contact of a pin type connector has always been subject to conflicting design requirements, particularly where the connector is utilized in a harsh temperature and vibration environment. Typically, in spring loaded contacts, a tight contact spring is desired in order to obtain good electrical and mechanical contact with the pin. On the other hand, the spring force should not be so great that the parts are difficult to mate and unmate. Hence, a flexible spring is required not only to facilitate ease of mating and unmating, but also to allow for reasonable manufacturing tolerances insofar as the connector and pin dimensions are concerned. However, if the spring is made too flexible, it may exert insufficient force to hold the pin particularly under conditions of high temperature and severe vibration. in the known prior art devices, the spring must be sufficiently thick to produce the desired spring force. However, it has been found that such a spring is often permanently deformed (i.e., takes a permanent set) when the connector is in a high temperature environment and an oversize or maximum size pin is inserted. It is obvious that if the spring is sufficiently deformed to take a permanent set" the spring will no longer exert the required force on the pin when a smaller pin, but one still within tolerance, is utilized and hence the connector fails. Hnece, a need exists for a pin type connector utilizing spring force to retain the pin in which the force exerting spring member is not deformed easily and thus, applies proper spring force to the pin even under severe environmental conditions.

Applicant has found that a multiple spring arrangement in which each spring member is extremely flexible and can be substantially deflected without permanent deformation, results in a connector which provides firm engagement at high temperatures and under high vibration levels without risking permanent deformation of the spring member.

Applicant has further found, that by utilizing a plurality of curved leaf springs of different widths, it is possible to produce a tapered spring assembly which fits easily within the circumference of a cylindrical socket member thereby allowing maximum spring force with minimum socket size.

It is therefore a principal objective of the instant invention to provide a connector assembly having a spring socket which provides good contact, is reliable in operation, and is minimal in size.

Yet another objective of the invention is to provide a connector assembly having a spring socket assembly in which the springs are not subject to permanent deformation in use.

Yet another objective of the invention is to provide a connector socket contact assembly utilizing a plurality of resilient leaf springs to provide maximum compressional force while minimizing the possibility of deformation.

Yet other objectives and advantages of the instant invention will become apparent as the description thereof proceeds.

The various advantages of the invention may be realized in one form thereof by providing a connector assembly utilizing a cylindrical spring loaded socket having a spring retaining slot in one portion thereof. A plurality of curved resilient leaf springs are positioned in the leaf retaining slot and project partially into the bore of the connector socket. A restraining sleeve is positioned over the socket and over the leaf spring assembly to provide a restraining member for the springs to allow deflection of the leaf springs by the pin without permitting permanent deformation thereof. By use of a plurality of leaf springs, the necessary spring force is realized, while at the same time, the individual leaf springs are sufficiently thin and flexible to allow maximum deflection without permanent deformation. in addition, the individual curved leaf springs of different widths so that the spring assembly is tapered thereby permitting a plurality of leaf springs to be positioned in a minimum circumference. In this fashion, a very small, and reliable connector assembly is made possible which produces positive engagement of the connector pin in the most severe environments of temperature and vibration.

The novel features which are characteristic of this invention are set forth with particularity in the appended claims. The invention itself, however, both as to its organization and method of operation, together with other objectives and advantages thereof, may best be understood by reference to the following description taken in connection with the accompanying drawings in which:

FIG. 1 is an exploded perspective of the pin and socket connector assembly of the instant invention.

FIG. 2 is a partially broken ray view of the connector socket contact assembly.

FIG. 3 is a sectional view taken along the lines 3-3 of FIG. 2.

FlG. 1 shows an exploded perspective view of a preferred embodiment of the connector utilizing a multi spring socket assembly to provide firm, positive engagement of the contact pin, while at the same time, minimizing the size of the connector socket and preventing permanent deformation or set of the springs. The contacts shown in FIG. 1 consists of four major components including a contact pin 1, a socket contact member 2, a retaining sleeve 3 fitting over the socket, and a multileaf spring assembly 4 which fits in the socket and is retained firmly in position by retaining sleeve 3.

Socket 2 includes a pin retaining bore 5 extending through the center of socket body 6. A spring retaining slot 7 is provided in the upper surface of socket body 6 and communicates with bore 5. The curved, resilient, leaf springs 4, presently to be described, are positioned in the spring retaining slot and extend partially into bore 5, and are held in position by means of a retaining sleeve 3.

A shoulder 8 is provided at one end of the main socket body to provide a stop for sleeve 3 when in the assembled position. A groove 9 is provided at the other end of the socket so that retaining sleeve 3 may be crimped into the groove in the assembled state for permanent retention of sleeve 3. A conducting stem 10 extends from shoulder 11 and is connected, as by soldering or any other suitable means, to a wire or connector which may for example, be attached to a sensing element such as a thermocouple.

Spring assembly 4 is shown as consisting of three thin, resilient leaf springs 11, 12 and 13, each of which is curved along the longitudinal axis. Springs 11, 12 and 13 are of the same length but of different widths so that when in the assembled state, the multi leaf spring assembly has a generally tapered shape along the radial direction so that the entire spring assembly fits easily within the circumference of the main body thereby minimizing the diameter of socket 2. The lower and widest spring 13 rests, when in the assembled position, on the lower side walls 14 of leaf retaining slot 7 and supports the remaining leaf springs 12 and 13.

Contact pin 1 consists of a pin element 15 which is received in socket bore 5, a shoulder 16 which supports the pin and fits into and is positioned by an insulator in a complete connector assembly, and a stem 16 to which a suitable lead or wire may be soldered or otherwise affixed for connection to any suitable utilization circuit such as a meter or indicator.

Spring retaining slot 7 in connector socket 2 permits leaf springs 11-13 to project into bore so that pin has to be pushed firmly into the socket and the spring assembly extends spring pressure against socket pin 15 to retain it firmly in position. Since each of the leaf springs 1 1, 12 and 13 are thin and resilient, the individual leaf springs can be deflected a substantial distance without permanently deforming the individual leaves which are retained in position by retaining sleeve 3. A firm and very positive spring pressure can be exerted against 15, while at the same time, preventing any possibility of deformation of the leaf springs by an oversized or maximum sized pin or by use of small diameter test probes.

FIG. 2 illustrates the connector contact in the assembled state. The three leaf springs 11, 12 and 13 are positioned in slot 7 and the retaining sleeve 3 is positioned over the main body of the socket and rests firmly against stop 8 at one end of the socket. The other end of the retaining sleeve is crimped, as shown at 16, firmly into groove 9 of the socket so that once assembled, the sleeve is retained permanently on the socket. It is also apparent that a clearance 17 is provided between the middle of the springs and retaining sleeve 3 to allow for upward deflection of the leaf springs as the pin is inserted, while at the same time, limiting the maximum displacement of the individual leaf springs. The latter is of significance in that it guards against permanent deformation of the spring assembly, not only by oversized pin but by the insertion of test probes by technicians or assemblers. Without the presence of the outer sleeve, the leaves though thin and resilient, could eventually be distorted sufficiently by a test probe to be deformed permanently and effectiveness of the connector destroyed.

When in the assembled state, it can be seen that the longitudinally curved leaf springs project into the bore beyond the wall thickness of the socket so that the clearance between the lowest part of the spring and the lower wall is less than the minimum diameter of the pin. As a result, insertion of the pin into the bore of the contact assembly forces the spring upward exerting spring force against the contact pin retaining it firmly in position even under conditions of severe vibration. At the same time, since each of the spring elements is very thin and highly resilient it may be deflected substantially without deformation whereas a single spring having the same thickness as the three leaf springs would be deformed by an oversized pin or a test probe.

FIG. 3, taken along line 33 of FIG. 2 shows the tapered configuration of the multi leaf spring assembly. Thus, the lower leaf spring 13 is positioned to rest directly on the lower side walls 14 of leaf retaining slot 7 and the remaining leaf springs 12 and 11 are stacked in a radially outward direction. lt can be seen that the width of successive leaf springs is narrower than that of the proceeding one, therefore providing a tapered configuration. It will also be apparent that by virtue of this arrangement, it is possible to mount the entire leaf spring assembly with a minimal circumferential dimension of the socket. Obviously, the lowest leaf spring must be wide enough to rest securely on the lower wall 14 of the retaining slot; otherwise, the spring assembly even if only slightly cocked falls into the bore and the entire connector assembly becomes inoperative. If the remaining leaf springs 11 and 12 were of the same size as the lowest one, it is obvious that the upper spring would be wider than the chord of the circle at that portion of the socket and hence in order to accommodate a single leaf spring or plurality of leaf springs of the same width a socket of a larger diameter would be required. By tapering the longitudinally curved resilient leaf springs in the manner shown, the overall size of the socket and the connector assembly is reduced while maintaining the desired spring force. The distance 18 between the lower surface of leaf spring 13 and the bottom wall of socket body 6 is less than the minimum diameter of the contact pin element 15 so that insertion of contact pin 15 forces leaf springs l1, l2 and 13 against the retaining sleeve thereby exerting a positive force on pin 15. It will also be apparent from the previous description of FIG. 2 that because the spring is curved along its longitudinal axis the ends of the leaf springs extend upwardly so that the pin when initially inserted at the bore passes by the end portion of the pins and engages the springs only near the center portion where the spring extends furthest into the bore. The maximum deflection permitted of the springs is the distance shown at 17 between the topmost spring and the wall of retaining sleeve 3. Hence, the deflection through which the spring can be forced either by an oversized pin or by a test probe is limited thereby preventing permanent deformation or a permanent set" of the leaf springs which could result in the loss of good contact pressure between the contact and the pin.

it will be apparent from the description heretofore provided that a pin and socket connector assembly has been provided which is small in size, provides positive engagement and good spring pressure, while at the same time, providing the flexibility in the spring assembly to provide for easy mating and unmating of the connector and at the same time, preventing permanent deformation of the springs by oversized pins or test probes. Therefore, a highly reliable, compact, and very effective connector assembly has been provided which may be utilized without loss of effectiveness in the most severe of temperature and vibration environments.

While a multi spring assembly utilizing three springs has been illustrated as the preferred embodiment, it will, of course, be obvious that the invention is not limited thereto since more or less of the springs, depending on the amount of force required, and the size of the connector pins, etc., may be utilized.

While a particular embodiment of this ivnetion has been shown and described above, it will, of course, be understood that the invention is not limited thereto since many modifications may be made. It is contem- What is claimed as new and desired to be secured by Letters Patent of the United States is:

1. In a spring loaded pin and socket connector, the

combination comprising:

a. a socket contact member including,

1. a socket member having a bore for receiving a pin,

2. a retaining slot in said socket member communicating with said bore for retaining a pin retaining means,

3. a spring assembly of tapered construction in the radial direction including a plurality of resilient leaf springs positioned together in said retaining slot to provide a spring loaded contact, each of said leaf springs being of a different width so that said leaf springs when nested together form said tapered spring assembly,

4. a retaining sleeve positioned on the socket to cover the retaining slot to limit deflection of said leaf springs to prevent deformation of said springs.

b. a pin member including a cylindrical pin portion adapted to engage the said spring assembly in said bore to provide firm mechanical and electrical contact between said pin and socket.

2. A connector contact assembly comprising:

a. a socket member having a central bore for receiving a connector pin,

b. a retaining slot in said socket member communicating with said bore,

c. a spring assembly of tapered construction in the radial direction including a plurality of resilient leaf springs curved along their longitudinal axes and extending into said bore to provide a spring contact in said bore, each of said leaf springs being of a different width so that said leaf springs when nested together form said tapered spring assembly,

d. a retaining sleeve positioned on the socket to cover the retaining slot for limiting the deflection of said leaf springs to prevent deformation of said springs. 

1. In a spring loaded pin and socket connector, the combinatioN comprising: a. a socket contact member including,
 1. a socket member having a bore for receiving a pin,
 2. a retaining slot in said socket member communicating with said bore for retaining a pin retaining means,
 3. a spring assembly of tapered construction in the radial direction including a plurality of resilient leaf springs positioned together in said retaining slot to provide a spring loaded contact, each of said leaf springs being of a different width so that said leaf springs when nested together form said tapered spring assembly,
 4. a retaining sleeve positioned on the socket to cover the retaining slot to limit deflection of said leaf springs to prevent deformation of said springs. b. a pin member including a cylindrical pin portion adapted to engage the said spring assembly in said bore to provide firm mechanical and electrical contact between said pin and socket.
 2. A connector contact assembly comprising: a. a socket member having a central bore for receiving a connector pin, b. a retaining slot in said socket member communicating with said bore, c. a spring assembly of tapered construction in the radial direction including a plurality of resilient leaf springs curved along their longitudinal axes and extending into said bore to provide a spring contact in said bore, each of said leaf springs being of a different width so that said leaf springs when nested together form said tapered spring assembly, d. a retaining sleeve positioned on the socket to cover the retaining slot for limiting the deflection of said leaf springs to prevent deformation of said springs.
 2. a retaining slot in said socket member communicating with said bore for retaining a pin retaining means,
 3. a spring assembly of tapered construction in the radial direction including a plurality of resilient leaf springs positioned together in said retaining slot to provide a spring loaded contact, each of said leaf springs being of a different width so that said leaf springs when nested together form said tapered spring assembly,
 4. a retaining sleeve positioned on the socket to cover the retaining slot to limit deflection of said leaf springs to prevent deformation of said springs. b. a pin member including a cylindrical pin portion adapted to engage the said spring assembly in said bore to provide firm mechanical and electrical contact between said pin and socket. 